1826: William Eusebius Andrews, Review of Fox's Book of Martyrs, WE Andrews, pp. 386-7:

At length, recommending himself to God, he let go one end of his cord, and suffered himself to fall down upon an old shed or penthouse, which, with the weight of his body, fell in with great noise.

An apartment or suite found on an upper floor, or floors, of a tall building, especially one that is expensive or luxurious with panoramic views. Sometimes these are located just under "penthouse mechanical" floors.

An odd derivative of real tennis lasted until the latter part of the eighteenth century at Rattray in Perthshire. It was played in the churchyard by two pairs of men, and the method for starting the play was to throw the ball onto the church roof, using it like the sloping penthouse of the tennis court.